There are many applications which require the lubrication of surfaces to reduce friction and wear. One such application is in the railroad industry where a locomotive wheel flange contacts a rail resulting in frictional build-up of heat and wear both to the wheel and rail. Excessive frictional contact between rail and flange is undesired because the amount of lost energy can be quite appreciable especially in instances where a locomotive pulls approximately one hundred cars, each of which is subject to frictional heat build-up and wear. It has been estimated that a significant savings of locomotive fuel requirements could be obtained if the energy lost due to the frictional engagement between rail and wheel could be reduced. It thus is highly desirable to minimize the effects of frictional engagement between the wheel flange and the rail.
One method for reducing friction and wear has been to lubricate the area between the wheel flange and rail. Several efforts have been made to apply the proper amount of lubricant at the desired location. One such system is disclosed and claimed in our pending patent application Ser. No. 785,571 filed Oct. 8, 1985 entitled "Wheel Flange and Rail Lubrication Apparatus". In the lubricating system disclosed in that application, we employ a lubricating nozzle assembly in which a nozzle is located contiguous to the zone of lubrication between the wheel flange and rail. While the lubricating system disclosed in our pending application performs satisfactorily in most instances, there are occasions where the shot of lubricant delivered to the area to be lubricated is not entirely satisfactory. It has been found that, in some instances, the lubricant does not properly lubricate the desired area because of inconsistent lubricant delivery pressure. The delivery pressure of the aforementioned system is dependent upon and essentially identical to the inlet pressure, and significant inlet pressure variations can be experienced due to temperature fluctuations in the lubricant line which supplies lubricant to the lubricating nozzle. The pressure may vary by a factor of two (2) with a 20.degree. F. temperature change.
What is desired is to have a relatively smooth and consistent shot of lubricant delivered to a confined area of the wheel flange and rail by a lubricating system which is relatively insensitive to lubricant pressure variations at the inlet to the lubricating nozzle.
A pressure multiplying piston assembly in the lubricating nozzle regulates the lubricant delivery pressure by utilizing a readily available supply of compressed air which is maintained within a narrow pressure range and is independent of temperature variations.